I would suggest that why don't you readup the mechanism of DNS assay and you will find the answer yourself. You have asked a very basic question in biochemical techniques.

Sir, I read the mechanism and I understood that different reducing sugars give different colors.

On the other hand, there are some literatures where people have used maltose for calibration and studing the degradation of starch by amylase. In degradation of starch by amylase, other reducing sugars will also be formed.

Best way then would be to use glucose (dextrose) for calibrating curve.

Sir, in starch degradation - maltodextrin, glucose, maltose everything will be formed and depending on their percentage available, color will be generated.

Then how can I take only one carbohydrate for calibration?

Let anything be formed in starch degradation. you can not estimate or quantitate maltodextrin or maltose (disachharides) by simple DNSA method. It will only give you the results in terms of glucose. For quantitation of maltodextrin read the first enclosed article (it has been published in Research gate. For Maltose quantitation read the second reference.

Thank you Sir. I will go through the papers suggested by you.